Pyrometer.



No. 846,998. PATENTED MAR. 12, 1907.

J. F. HAMMOND. PYROMETEE.

APPLICATION FILED 1:011, 1905.

.while the other may be an alloy of platinum f! JOHN F. iliiltiOND, OFBEEWSTER, NE Ji YGRK, Xi

WHITE DENTAL IVLLNUFACTURHQ Sill/WANT, x EYLVMIIA.

P il

u i as Ho. scenes.

Patented rim-eh is, 1907.

Application filed November 1, 12 35. Serial 1% 285,380.

il further object of my invention is to lo- To all whom may concern:

be tween thethermo- Be it known that l, JOHN r: a citizen of the UnitedStetes, res

the point of un -"u e' couple and the gelvenomctcr-conductors be-Brewster, in the county ofPut-mcn and State yond or outside the radiantheat zone of the of New York, have invented ccrtsin new furnace, for ifthis point of union be within and useful Improvement in Pyrometers; ends d heat zone the copper gelvenometer-con- I do hereby declare thefollowing to he uctors, acting by contsctwith the dissimilar clear, and.exact description of the invention, metals of the couple, will up itseperete such as will enable others skilled in the srt to thermo-electrio action which will tend to neuwhich. it eppertsins to make 1.1161use the trelize, or ct least vitiete, the reading of the same.wgel'vsnometer as a true index of the tern-- My invention relates toelectric pyrometers persture ithin the muliie. I

of the well-known thermocouple type, ith this and other objects in viewmy inand is applicable to furnaces 01" various kind s, vention consistsof the improvements herein but particularly to electricnitride-furnaces. shown and described, and pointed out in the Pyrometersof this class usually consist of e thermocouple located or adapted to beinserted Within the mufiechamber and composed of, two members or wiresof dissimiler metals united by a smell bell, a gslvenonieter external tothe furnace, and electric connec tions between the free ends of saidthermocouple members snd said gelvcnometer. One of the members or wiresof the thermocouple as now made is of pure platinum,

specification r in the accompanying drawings, illustratinga, suitableembodiment of my invention, Fig e l is a view in side elevation of swellltncwn form oi electric furnace having my invention applied thereto.Fig. 2 is a. face view of cgelvcnometerof the kind Iprefcr to use withmy invention. Fig. 3 is ii View in side clcvetiouof my invention on alarger in the preceding views and showing portion of e furnscemuli'le invertical ion. d is a top or plan View of the parts shown in Fig. 3. Fig.

and: rhodium. The electrical connections -l between the couple and'gclvunometer conso sist of conductors which for chcspness are usuallyof copper.

\Yhen the couple is hosted, a very light electric current is generatedtherein, the strength of which is proportioned to the de gree of heat inthe muffle. The force oi? this current, which is known as the cou ilecurrent and which is entirely distinct 'rorn the current used to heatthe muffle of an electric furnace, .is indicatedupon the g2ilvanometer,which by suitable calibration will give accurate readings of the exacttemperature of the mufiie. j

The general object of my invention is to improve the electricalconnections between the thermocouple and gelvenometer, one of my'objectsbeing to provide a. readily-sepsreble contact between said couple andthe galvenometer-conductors.

I Another object. of my invention is to permanently attach thethermocouple to the muflle, so that it practically becomes apartthereof, with no outside projecting'wires or mechanical connections tointerfere with the removal or replacement of the muflle from or to itssupport. I

o is, a front or end view of the upper portion of thethermocouple-extension carriers. Fig. 6 is e sectional view, on a. stilllarger scale, of the clip for uniting gelvenomctor-conductors.

lhe furnace to which I have herein shown .1131 improvements as beingapplied is "the well-known Hammond electric furnace, for which LettersPatent of the United States No. 688,170 were granted me December 3,1901, although it is to be understood that my present improvements areapplicable to other forms and kinds of furnaces. T his furnace, asindicated in the secon shying drawings and more fully shown on describedin the before-mentioned Letters Patent, comprises the following parts: Atwoart muffle A A, consisting of an outer mete bcrrel A and an innerfire-clay mufile A, is mounted over a mufile proper is inclosed in themetal barrel, and the latter is provided with notched prosecured to theB. The front end of the claims at the conclusion of the followin thethermocouple extensions and base or slob B, of insulating material. The

jections a at front and rear, which detecheblyengage similar rojectionsc on uprights CO,v

.base is a rheostat inolosed in an. open-work frame E. Suitaltleelectric spring-contact devices (also not shown herein) are providedbetween the mutile and rheostat, while a knife-switch F,controllingdever G, contactstops, and binding-posts are mounted upon thebase B. By means of this construction the muffle may be uic-kly removedfrom the furnace by simply ifting the barrel from its supports andreplacing it again withoutderanging the electrical connections and without the necessity of disconnecting'or connectingthe same, this heingprovided for hy the spring-contact device I Having hrietly descrihed oneform ofil'urnace to'which my invention is ap licahle, I

will now descrihe the invention itse fifirst referrin to thethermocouple and the improve l manner of applying it to the muffle Thethermocouple ll consistingof two members or wires of dissimilarmetalsunited at thcir. inner ends ly a hall ll, as usual, is located ,in therear of the niufile-chamlter A. near the top thereof, where it will heleast likely to interfere'with the object's placed in the furnace. Thewires pass through the rear wall of the mutile in which they are cmbedded and on the outsideot which they are exposed, as st ll"; Insteadotpcrnuttmg the wires to PIOJOML lreyond the outside of the muffle forthe lpurpose of making electrical connection witl a galveuometer, as iscus toma-ry, they are'hcnt. and extended a short. distance close to orin contact with the exterior motile-wall. The exposed portions ll of thewires are shown as extending "vert iciilly with their ends penetratingthemutlle for the purpose of more securely holding them in place. Itshould he olrscrvcd that the thermocouple mey'l c located in any otherposition-fmm that just dcscrilzcd which is l:cst adapted fortheparticular construction of connecting'de ices next to l-e dcscril ed,

A galvanometcr l of any, suitalzle torm and construction may he locatedin any conven- .icnt position near to or far from the turnacc,

as may he desired. in the present instance it is mounted in an inclinedposition upon the platform D to therear of the furnace, where it isclearly visilile to the person ope-rating the furnace and not in the wayof the same.

The usual electrical connection,lzetwcen the thermocouple andgalvanometer consists of copper conductors extendmg t'rom the gal:

a iases and connecting electrical couplings possesses other advantages.

Two short lengths of wire K K, each of the same metal as the members ofthe thermocouple with which thcv respectively come in contact, areinterposed between the exposed portions H of said thermocouple membersand the galvanomctcr-conductors J J. These.

wires K K may be regarded as exterior extensions of the thermocou le.members and provide a readily-sepawill be hereinafter rcfcrrcc to asthermo-.

couple extensions.

sions K is supported by means that will cause said extensions tonormally hearupon the exposed portions of the thcrmocou )le members, therear plate of the furnace 9- ing cut away for t iis purpose. In this waya yielding and rcmlily-scparahle contact is provided between thethermocouple and its extensions. The preferred means, as shown, consistsof a carrier M for each extension, the pair olcarricrs being mountedside by side upon the turnacwhase B and hcst made inde- Eaeh of theseexten peudcntly movahlc or adjustahlc toward and p away from the mullle.Surrounding each extension K 1s a tube L, of riorneonductmg material, asglass or porcelain, molded or otherwise formed upon the extensions andntl'ording means for adjustahly attaching said extensions to andinsulating them froni .the carriers, said tuhes being held by carrier-.clamps M7. The wire of which each cxtension is composed protrudes heyondthe front end of its tuhe, across which surface for contact with theexposed thermocouple against which it is adaptcd to hear,

while the rear end of said wire is cxtcndcd some distance hcyond theoiposite end of the tuhe for conncctiou with thegalvanometcrconductor.

it may be bent, shown in F g. 5, to atl'ord a larger hcarmgrod Thecarriers shown are piyotcd at m to a plate N, secured to the furnace, inthis instance to-the hose ll, so as to have a slight rocking movementindependently of (uch other toward and away from the mutlle. A spring(l, interposed llt tween the plate N and an arm Bl oi the carrier, strvcs to force the carrier forward and cause the (Kit usiou to hearagainst the (Xpost'd thcrmocouplr mcmher, while another arm M of thecarricr, comingin contact with :1 lug n of thc plutc limits the forwardrocking movcmcnt ol' the carrier.

Instead of uniting the couple extensions and galvnnometor-conductors 111the ordinary manner I n'ct'cr to first connect. the conductors to thecarriers for the purpose of lakin the-strainer pull of the conductors ofsaid extensions." For this purposethe can riers are eschformed with anarm or exten sion M having a split clamp M and screw m for holding theconductors. n split clump P may be'employed for uniting the conductorswith the respective extensions.

The thermocoupl it will be seen, is built in the muiii'e, thusbeing apart thcreoi and movable therewith. The extensions of the thermocoupleare alwaysin. position to make proper contact with the thermocoupleitself, the spring-carriers forcing said extensions against the exposedwires of the thermocouple when the mufiie is in position. this Way themuflle may be readily placed in position or removed therefrom Withoutthe necessity of making or breaking any connections or couplings and, infact, Without paying any attention Whatever to the electricalconnections between the thermocouple and ga n vanometer.

By connecting the galvanometer-wires with the thermocouple extensionsinstead of di-- rectly with the thermocouple itself the necessity ofconnecting and disconnecting the galvanometer-wires each time the mufiieis placed in position or removed therefrom is obviated. Moreover, bythis means the point of connection between the thermocouple Wires andthe galva-nometer-wires msy be located beyond the radiant heat zone ofthe 'mufile without having the thermocou le-wires projecting outside ofthe mufiie. As arge portions of the thermocouple exten tions are exposedto the air, there is no lie.

bility of these extensions becoming heated, which would interfere withthe correct reading of the galvanometer.

Another advantage of my invention is the fact that the thermocouple isentirely relieved of all strain or pull to which the gelvunometer-wiresmay be subjected in the op eration of the furnace. Should these wires heaccidentally pulled or in any way dis- 'turbed, the couple extensionswill simply be withdrawn from contact with the thermocouple, the effectot which will be to interrupt the pyrometer-current for the time beingJust as soon as the pull on or the interruption of thegalvanometer-wires ceases the springcarriers ,will automatically throwthe extensions intoncentact with the thermo couple, whereby thepyrometer-current is lli'lmedlately restored. Furthermore, theextensions themselves are relieved of strain from pull of thegalvanometer-conductors by connecting said'galvanometer-conductors tothe carriers in rear of the umon between the some.

y so doing,'the pull of said conductors comes upon the carriers and notupon said exten sions.

The carriers may consist simply of platesprings; but my invention is notconfined to the precise form of carrier shown nor to any other detailsof construction herein illusrsted end. (le ibed i'clairu asinvention- 1. A furnace-muffle having s thermocouple mounted therein andtorming 8. port the mettle-chamber with its mem ers extemi through thewells ofssid mufiie and ere posed upon the outside thereof, the exposedportions oi said LLQZHlJiBIi'S bein bent and extended along the outerwall oi the muide.

combination of e removably-supported muf ile, s thermocouple mountedtherein. and exelectricsl connections between seid thermocouple andgalvsnometer, and springrectw stee carriers for supportingseidconnections in yielding and sepsrshle eontect with the exposedthermocouple.

In en electric pyrornetenhirnsce, the combination of s 'mufile, sthermocouple mounted therein and exposed on the outside van'ometer andthermocouple extensions, and spring-actuated carriers for said thermocoupie extensions.

5. in ou electric pyrorneteniuro aee,- the comhin ation of e removeblysupported muiiie, a thermocouple mounted therein and exposed on theoutside thereof, said couple consistin of two members of dissimilsrmetwith which it is adapted to come in contect, springmctuated carriersfor supporting. said extensions in yielding and sepsrsbie contest withthe exposed thermocouple members, conductors" of n different metel fromthe thermocouple and it's extensions connected to ssid extensions at apoint beyond the ratdiant heat zone of the furnace, and c gel In outedtherein and exposed upon the outsi 0 thereof, thermocouple extensionsheaving posed on the outside thereof, a galvenometer,

thereof, said couple consisting of two mem--.

.vanometer, conductors between said gal venometer to which saidconductors are con 6. in an electric pyrometer-furnaoe, the

thereof, ssid thermocouple bein located in in an electric pyrometeiiurnace, the i sls, two thermocouple extensions each of the some metalas the thermocoupie member no permanent connection with saidthermocouple, non-conducting tidtes surrounding said extensionsWhichproiect beyond the ends thereof, springmct'uated carriers forsupporting said tubes and causing the forward end of each thermocoupleextension to bear 'upon the exposed portion of-its respective sions.

In testimony whereof I affix my signature in presence of two witnesses.

' JOHN F. HAMMOND. Witnesses:

SEYMOUR CAsm, G. A. GULOWSEN

